1. Field of the Invention
This invention relates to drier appliances and in particular to control means designed to conserve electrical energy.
2. Description of the Prior Art
Thomas R. Smith, U.S. Pat. No. 2,743,530 discloses control means which are used to prevent overheating and damage to the clothes. In this particular invention, a tumbler type clothes drier is provided with means for heating the clothes to evaporate the moisture therein, the drier is further provided with a temperature responsive thermostat within the drying chamber holding relay connected in series with the heating means circuit for delaying operation of a timer motor until after the thermostat is operated to deenergize the heating means. Upon deenergization of the heating means, the relay acts to prevent reenergization of the heating means even though the thermostat moves back to its closed position.
Roque Denis Marcade, U.S. Pat. No. 4,112,588 is directed to a control for use in a dryer appliance having a heating means including an electrical component, thermostatic switch means connected in series with the component for operating the heating means as an incident of the temperature sensed by the thermostat means being below a preselected temperature, a timer including a timer motor, and a control switch connected in series with the motor for causing operation of the timer. A capacitor is connected from between the timer motor and the control switch to between the thermostat means and the electrical component for connecting the timer switch in series with the electrical component when the control switch is open. The capacitor further effectively connects the timer motor with the thermostat switch means so that the series connection of the timer motor and the capacitor is effectively shorted out by the thermostat switch means when the thermostat switch means is closed to energize the electrical component.
The capacitance of the capacitor is preselected to form, with the inductance of the timer motor, a series resonant circuit condition when the thermostat switch means and the control switch are open wherein the voltage across the timer motor is at least a minimum operating voltage of the timer motor and the voltage across the electrical component is less than minimum operating voltage to cause effective heating operation thereof.
Curran D. Cotton, U.S. Pat. No. 4,083,118 is directed to a time and temperature control circuit for fabric dryers in which the heating element is center tapped to control the heater wattage. The control includes a resistive heating element in series with high limit and cycling thermostats and connected across the two power lines of a three wire alternating current power supply. The drive motor of the timer is electrically connected between the junction of the two legs of the heating circuit and the neutral wire of the power supply. The impedance of the timer drive motor is high compared to the resistance of the heating element; therefore, when the heating element is energized for drying fabrics, the current flow to the timer drive motor is negligible and the timer will not advance. When the cycling thermostat in one of the legs opens at a predetermined temperature, the heating element will be deenergized and current will flow in the other leg and neutral lines and the timer will advance until the thermostat closes to reenergize the heating element.